Overview of (1→3)‐β‐D‐glucan immunobiology

Abstract

Glucans are (1→3)‐β‐D‐glucose polymers that are found in the cell wall of fungi, bacteria and plants. Glucans are known to stim ulate humoral and cell‐mediated immunity in humans and animals. In addition to the potent immune stimulatory effects of (1→3)‐β‐D‐glucans, there are a number of toxicological effects associated with exposure to the water‐insoluble, microparticulate form of the polymer. Recent investigations have suggested a potential role for (1→3)‐β‐D‐glucans in inhalational toxicity. Specifically, (1→3)‐β‐D‐glucans have been implicated in the symptomatology associated with ‘sick building’ syndrome. The mechanisms by which (1→3)‐β‐D‐glucans mediate immune stimulation and, perhaps, toxicity are currently under investigation. It is now established that (1→3)‐β‐D‐glucans are recognized by macrophages and, perhaps, neutrophils and natural killer cells via a (1→3)‐β‐glucan specific receptor. Following receptor binding, glucan modulates macrophage cytokine expression. Here we review the chemistry, immunobiology and toxicity of (1→3)‐β‐D‐glucans and how it may relate to effects caused by inhalation.